It is obvious that most prostitutes are not there by choice, by a mature rational decision. Most prostitutes are victims dragged into it by ignorance, by poverty, by drug addiction, by human traffic and exploitation. The psychological damage is done too fast too soon, rehab is hard if not impossible. In many cases they become pregnant and now they have another mouth to feed. If the kid is a girl, very likely to learn to do what the mother does.
It should be a crime! However, only the buyer should be punished, as it would be very unjust to punish the victim twice.